64 



American Midland Naturalist Monograph No. 1 



Eyes.- 

 Anus. 



-Absent. 

 —In an oval 



pattern. 



LARVA 



Oval, wider anteriorly, mouth parti visible from above. Integument thin, 

 striated; with sparse hairs in a symmetrical pattern. Length, not including 

 mouth parts, 0.66; width, 0.48. 



Hypostome. — Hypostome moderate in length, apically rounded; denticles 

 2 /o, occupying about the apical one-third and with the lateral teeth larger. 

 Posthypostomal hairs long. Length of hypostome about 0.1. 



HOSTS 



Ornithodoros parkeri was originally described from specimens that had 

 been taken from Citellus sp., Lepus sp., and Cynomys sp., forty miles south- 

 west of Casper, Wyoming. In our field experience it soon developed that while 

 scattering specimens could be collected on animals away from their burrows, 

 the tick was to be found more regularly and sometimes in abundance in the 

 burrows. 



Jellison (1940) examined 18 burrows and nests of the burrowing owl, 

 Speotyto cunicularia, in Washington and nine were infested with O. parkeri. 

 In nest 106 he took 491 ticks, and in nest 108, he took 360 ticks. Some of 

 the nests containing fledglings had ticks that were fully fed, and microscopical 

 examination showed that they contained avian blood. Thus it is evident that 

 the burrowing owl is a natural host of O. parkeri. 



Fig. 26. Distribution of Ornithodoros parfyeri Cooley. 



